From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com [IPv6:2a00:1450:400c:c09::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 08DEB3CB35 for ; Wed, 22 Aug 2018 05:30:27 -0400 (EDT) Received: by mail-wm0-x244.google.com with SMTP id t25-v6so1463285wmi.3 for ; Wed, 22 Aug 2018 02:30:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heistp.net; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=E5EyHhrbcLGXGGdirZ7jbvnoEuN3sM0xcmHYWNmUPV4=; b=i3PATt+TZ+nsJ14hhQTh0Zn0lmMay5h+Fl45bKOdKixW3v5uLQjiFzKTZwTtiD+Ybe p0FUdMZmRwFksBbzVcVu2mpCBSEFMYZ2XDaT+MF5K++zSMEzxc4SdBNMiVDBFiJoYA+A cP3Vl5sFsnIHSxlIUR0VLGiYpP7VNf1Ck8ZDNYXA63odH95EU9FXeQNONTeDDJ1WFxER U+1IaTVXiYBtIEWX8En+tzWK8sVeH7Ex2DQKb/ZQfvZTqx+jAcaXLQSrWFX1zSiJ1ljI PMZxzuB+DI0u+p0AZ+jfIGS7VjJZQf/RzMT2eOisJgELnsl97dypbIpSV7f7QNR1Juce jqSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=E5EyHhrbcLGXGGdirZ7jbvnoEuN3sM0xcmHYWNmUPV4=; b=uLgvzeIS9r8ERyHpuAlxwgnjy6yYP9q7IdEJznZnKqg2lMtRG/6G2QMlIKM6IMfoeJ soValTYBkz0tsipd3XxugEC0lAUEdZ0ohnQlCFtWePlGY+nkfoD/LbHkNf7u0iNFf96z +kkojH6jV8ixfkhiKPd0m9iLfesHex4rFjODdRz648/8SjZ0bm0nbbdE0bH7D3Yiuzd2 ixJekQ1SCupncNUcmMoTJEU9u11Hu8GCD0Bf9NsO71kHgs4w02y60Ps1vxTC2u1E/jkh bAGVwz6a46Ld7Z7oF8YHiFU/hVSxt96zqeHUj/QwgvnHHL6Pa48muLU4/UX8dcl4uch8 jYCQ== X-Gm-Message-State: APzg51Bra8ISsmSwZVJE9gOWslHIVazOWyQwwlDk8Pyf9XkMb7EZiQSt lD6d3dRdkGPocH6UnU+csPywnvujqjk= X-Google-Smtp-Source: ANB0VdZT4EBRlams4jAe1VxMjM9siwQwLrjdyJCvUCDRc4cpett5EBw9O/01ePdiY8aeFp0wDzQuXA== X-Received: by 2002:a1c:e708:: with SMTP id e8-v6mr1900337wmh.134.1534930227165; Wed, 22 Aug 2018 02:30:27 -0700 (PDT) Received: from tron.lt2.drhleny.cz ([185.15.109.151]) by smtp.gmail.com with ESMTPSA id g133-v6sm1435805wmf.44.2018.08.22.02.30.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Aug 2018 02:30:26 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Pete Heist In-Reply-To: Date: Wed, 22 Aug 2018 11:30:25 +0200 Cc: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Cake List Content-Transfer-Encoding: quoted-printable Message-Id: <03B32CF6-2926-42A7-A407-CBD16BA38F0D@heistp.net> References: <87h8jze5hk.fsf@toke.dk> <85C60B2F-78D0-4AEE-871C-BB637785BF62@gmail.com> <4D28C453-5378-4A5B-9E05-874F36C4DB30@gmail.com> <878t5aedj5.fsf@toke.dk> <87d0uc9d2f.fsf@toke.dk> To: Jonathan Morton X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Cake] issue with Cake and bpf filter X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Aug 2018 09:30:28 -0000 > On Aug 22, 2018, at 8:17 AM, Jonathan Morton = wrote: >=20 >> On 22 Aug, 2018, at 12:06 am, Pete Heist wrote: >>=20 >> when fq_codel is the qdisc, the eBPF action is only called "once in a = while=E2=80=9D >=20 > One difference between fq_codel and Cake is that the former - which = has no shaper - will "bypass" packets when it's empty and there's no = back-pressure filling it. In that case no packet classification occurs = and filters will not be called. Or at least, that's how it used to be = set up; I haven't looked at it recently. Cake does not rely on the same = set of assumptions, so will always call the filter. Aha, that sounds likely, I=E2=80=99ll try with htb and a rate limit. = Testing with fq_codel was challenging as I had to =E2=80=9Cdo stuff=E2=80=9D= until my printk=E2=80=99s were eventually called, but it=E2=80=99s = easier now that I can use cake. I suppose in my case fq_codel=E2=80=99s = behavior would be ok in production, because if there=E2=80=99s no queue = then there=E2=80=99s no need to classify. Maybe in some other cases = (like gathering stats), it could be problematic.=